This goal of this project was to develop a closed, recirculating shellfish depuration system that is cost-effective and environmentally sound and that meets sanitation and other regulatory requirements.  The project was a collaborative effort between Washington State University and a shellfish producer (Taylor Resources, Inc., of Shelton, Washington).  The proposed research tasks were accomplished.  Major results obtained include waste excretion rates of Manilla clams under different temperatures, nitrification kinetics models and kinetics parameters, and UV disinfection efficiency and pertinent factors.  Values for a series of parameters were defined and recommended through this research project for design and operation of recirculating depuration/wet-storage systems.  A commercial-scale wet-storage system was designed and constructed at Taylor Resources, Inc.  Evaluation of the system showed satisfactory performance.  The products of the project also included six manuscripts for refereed journal papers, one Master's thesis, and five conference presentations.